Mycobacteriology Laboratory

Micobatteriologia

Referents: Prof. Maria Rosalia Pasca (Full Professor), Giulia Degiacomi (Associate Professor)

Co-workers: Deborah Recchia (Post-doc), Alessandro Stamilla (Post-doc), Ludovica Maci (Post-doc), Maria Concetta Marturano (Fellow)

 

1. Search for new antitubercular drugs and study of their mechanisms of action and resistance
Tuberculosis (TB) remains the major cause of mortality due to a single bacterial pathogen, Mycobacterium tuberculosis. In fact, TB caused by multidrug-resistant (MDR and XDR) strains of M. tuberculosis poses a serious public health threat worldwide. There is therefore an urgent need for new antitubercular drugs that can counteract the phenomenon of drug resistance. The research activity of the Mycobacteriology Laboratory has focused on the development of new compounds with antitubercular activity in the early drug discovery stages to identify and characterize their mechanisms of action and resistance. Gene regulatory systems applied to M. tuberculosis may be useful for the validation of cellular targets during the drug discovery process. In addition, the identification and validation of cellular targets is crucial in the process of characterizing the mechanism of action of such compounds. With gene regulatory systems designed specifically for application in M. tuberculosis, it is possible to construct conditional mutants that can also be used in the drug discovery process.
The Mycobacteriology Laboratory has identified the cellular target of benzothiazinones (doi: 10.1126/science.1171583), which are currently in phase II human clinical trials (Macozinone, BTZ043; https://www.newtbdrugs.org/pipeline/clinical). Thanks to the collaborations established during the previous European Commission-funded projects, we are studying the mechanism of action of new compounds active against M. tuberculosis and we are validating new cellular targets of M. tuberculosis.
Collaborations:

  • Makarov V (Russian Academy of Science, Mosca, Russia);
  • Mikusova K (Università di Comenius, Bratislava, Slovacchia);
  • Baltas M (CNRS, Tolosa, Francia);
  • Lherbet C (Università Paul Sabatier-Toulouse III, Tolosa, Francia);
  • Manetti F (Dipartimento di Biotecnologie, Chimica e Farmacia, Università di Siena, Italia).

2. European Regimen Accelerator For Tuberculosis (ERA4TB; IMI 2 - Horizon 2020)
Since 2020, the Mycobacteriology Laboratory has been one of 31 partners in the European Commission- funded project “European Regimen Accelerator For Tuberculosis” (ERA4TB; IMI 2 - Horizon 2020; Jan. 1, 2020-Dec. 31, 2026), which involves public and private entities with the goal of developing at least two or more new drug combination regimens ready for phase II clinical development (https://era4tb.org/). The Mycobacteriology group has been able to expand its expertise in order to evaluate the intracellular activity of new antitubercular and/or anti-virulence compounds. In particular, Granuloma-like structure (GLS) assay and ex-vivo infection model with THP-1 cell line were developed and implemented. We have also studied the mechanism of action of two compounds currently in Phase 2 clinical development (doi: 10.1016/j.isci.2023.106411) and are characterizing the mechanism of action of 4 antitubercular compounds, 3 of which are already in Phase I clinical trials.
Collaborations:

  • Cole ST (Pasteur Institute, Parigi, Francia);
  • Ramon-Garcia S (Università di Saragoza, Spagna);
  • Manganelli R (Dipartimento di Medicina Molecolare, Università di Padova, Italia);
  • Baulard A (Institut Pasteur de Lille, Lille, Francia);
  • Khisi Mdluli (Bill & Melinda Gates Medical Research, USA)
  • Natalia Serbina (TB Alliance, USA)

3. PNRR-PE13
The Mycobacteriology Laboratory is also part of the Project: “One Health Basic and Translational Research Actions” funded by MUR (PNRR Extended Partnerships; PE13_INFACT_PNRR - U.A. 14.01; INF-ACT) (11/2022-02/2026).
The main activities in which the Laboratory is involved are the implementation of new strategies to fight antimicrobial resistance in an Italian One Health context. In this project we are studying the mechanism of action/resistance of new drugs against M. tuberculosis (research line 1) and Mycobacterium abscessus (research line 5).
Collaborations:

  • Manganelli R (Dipartimento di Medicina Molecolare, Università di Padova, Italia);
  • Manetti F (Dipartimento di Biotecnologie, Chimica e Farmacia, Università di Siena, Italia).

4. Development of antibody-drug conjugation (ADC) strategies for tuberculosis control (PRIN 2022)
M. tuberculosis primarily resides in host macrophages that provide a refuge for the bacteria during infection. To eradicate intracellular M. tuberculosis, we are developing an antibody-drug conjugate (ADC) approach in collaboration with Prof. Petricci and Prof. Bottai. ADCs have been developed for the treatment of oncological diseases and recently adapted to infections caused by Staphylococcus aureus/Pseudomonas aeruginosa and may represent an innovative approach for the treatment of TB. The ADC strategy is based on the use of monoclonal antibodies (mAbs) linked to a cytotoxic/antibiotic drug in a way that allows precise drug delivery to the target.
The lack of commercially available mAbs directed against M. tuberculosis cell surface proteins may hinder the development of ADCs. Therefore, to identify potential candidate ADC molecule targets, we are expressing, by recombinant strains of M. tuberculosis, selected surface antigens modified to have the HA epitope of hemagglutinin as a tag. The HA tag is recognized by commercial anti-HA-specific mAbs. The anti-HA antibodies will be loaded with different payloads (i.e., anti-TB antibiotics). Next, the mAbs will be
evaluated for their intracellular activity in in vitro and ex vivo models.
Collaborations:

  • Petricci E (Dipartimento di Biotecnologia, Chimica e Farmacia, Università di Siena, Siena);
  • Bottai D (Dipartimento di Biologia, Università di Pisa, Pisa)
  • Delogu G (Dipartimento di Scienze Biotecnologiche di Base, Cliniche Intensive e Perioperatorie, Università Cattolica del Sacro Cuore, Roma).

5. Evaluation of the efficacy of the new antibiotic “VOMG” against Mycobacterium abscessus (FFC#9/2023, PNRR-PE13)
Among nontuberculous mycobacteria, Mycobacterium abscessus is becoming the most prevalent pathogen of global concern as it is associated with chronic lung deterioration in people with cystic fibrosis or other chronic lung diseases. M. abscessus is also intrinsically resistant to many drugs. To date, no specific antibiotic has been developed against M. abscessus; therefore, new effective drugs are needed.
Thanks to the funded projects obtained by the Italian Cystic Fibrosis Research Foundation (FFC#19/2018, FFC#14/2020, FFC#18/2021, FC#9/2023, PNRR-PE13), we have characterized the molecule named VOMG (Patent: PCT/EP2023/078712) as a new compound active against M. abscessus and with broad-spectrum activity against other pathogens (doi: 10.1016/j.ijantimicag.2024.107278). We used a multidisciplinary approach including microbiological, chemical, biochemical and transcriptomic analyses to validate VOMG as a promising anti-M. abscessus drug candidate. VOMG inhibits cell division, specifically the enzyme FtsZ.
Currently, through the FFC#9/2023 and PNRR-PE13 projects we are studying in detail the mechanism of action of VOMG and cell division in M. abscessus.
In addition, we are testing new classes of compounds against M. abscessus.
Collaborations:

  • Makarov V (Research Centre of Biotechnology RAS, Mosca, Russia);
  • Ramòn Garcia S. (Università di Zaragoza, Zaragoza, Spagna);
  • Cirillo D (IRCCS Ospedale San Raffaele, Milano).

6. Novel strategies against intracellular mycobacteria (PRIN2020)
Under the MUR-funded PRIN2020 project, host-pathogen interactions are being investigated to design a novel strategy to eradicate M. abscessus and M. tuberculosis using a multidisciplinary approach. Specifically, the Mycobacteriology Laboratory is contributing to the project by investigating two type 7 secretion systems present in M. abscessus (ESX-3 and ESX-4) involved in the early stages of infection by constructing and characterizing M. abscessus mutants that do not produce effector proteins.
Collaborations:

  • Rizzello L (Dipartimento di Scienze Farmaceutiche, Università degli Studi di Milano, Milano);
  • Manganelli R. (Dipartimento di Medicina Molecolare, Università di Padova, Padova).